High-potential strain-insulator.



-L. STEINBERGER.

HIGH POTENTIAL STRAIN msnu'roa.

"BD JUL 927,186, Patented July ii, 1969 2 BHEETS-SHEET 1.

N V E N T 0/? Z u 213 556572 berg er ATTORNEYS 1 n: xvg

7 WITNESSES M was L, STBINBERGER.

HIGH POTENTIAL STRAIN INSULATOE.

APFLICATION FILED JULY 30, 1906.

Patented 6,1909.

23H E 3 BET 2.

TOR

A TTORNE Y8 era-i dir UNITEU @TATES PATENT LClUlS STEINBERG-ER, OF NEW YORK, N. Y.

HIGH-POTE NTIAL STRAIN-INSULATOR.

Specification of Letters Patent.

Patented July 6, 1909.

Application filed July 30, 1906. Serial No. 328,32.

York, have invented new and Improved High-Potential Straim-Qhsulator, of which thcfollowing is a full, clear, and exact description.

My invention relates to strain insulators used in connection with electrical conductors, and more particularly to conductors adapted to convey currents of high potential.

Among the several purposes of my invention are the following: 1, to give the various parts of the strain insulator such conformity as will. confer upon themi a comparatively high degree of mechanical strength coupled with a high i'liclectric capacity; 2, to avoid surface leakage and danger oi arcing by pro- \dding disk-like members oi: insulating inaterial so sitinited as to virtually increase the distance between metallic portions to be insulated from each other; 3, to '{H'OVlilfi certain metallic p ts of the structure with sleeves ofinsulatiug material independent of the general body of insulating material used as a covering for the strain 4, to provide the body portion of the strain insulator with a groove whereby it serves as an insulator for supporting an electric conductor disposed at a right angle to the general direction of the axis of the strain insulator; 5, to so shape the metallic parts to facilitate the assembling of the device complete; 6, to provide an efficient bearing surface of insulating material so disposed that the mechanical stress is distributed throughout a comparatively large area, thereby tending to prevent distortionand also to prevent arcing; 7, to incorporate in the strain insulator a metallic l which is closed upon itself at a point embedded within the insulating material and provided. with jn'ojccting portions to be engaged by a tension member.

Reference is to be had to the accompanying lravx-ings forming part of this specification, in which similar characters of reference indicate corresponding parts in all the ligures.

Figure 1 is a ccntralvertical section through a strain insulator, made in accordance with my invention, and showing an electric conductor nosed at right angles to the gen- 32 a central electrical trade as vertical section upon the line 2-2 of Fig. 1, looking in the direction of the arrow, and showing the disposition of the stems 6, sleeves l0 and disk 4, and also showing the manner of mounting-a tie wire 25 so as to secure a conductor 24 resting upon the top of the strain insulator; Fig. 3 is a erspective view showing one of the links of the strain insulator, this link being provided with a closed portion which is to be completely embedded within the insulating material, and

with a threaded stud projecting from this link; and Fig. 4 is an elevation of the washer of insulation material, and which sustains the mechanical and dielectric stress of the device. I

A disk 4 of metal is provided with holes 5 of frusto-conical form and with stems 6, also of frusto-conical form, these stems being intermedi ate of the holes as indicated in Fig; 3, and joined by a bridge portion 7, the stems, bridge portion and disk thus constituting an endless or closed member. A threaded stem 8 is integral with the bridge portion 7, and projects therefrom. A threaded socket 9 fits rcvolubly upon the stem, and is provided with an eye 9. Fitting into each hole 5 is a sleeve 10 of frusto-conical Form and made of insulating material having a comparatively high. dielectric constant and a maximu m of so-called crushing strength, These sleeves 10 are of greater length than the thickness of the disk 4, and when fitted. into position each sleeve extends slightly from both ends of the hole in which it is located.

Frusto-conical bolts 11, each provided with a threaded cylindrical portion 12, are fitted into the sleeves 10. The threaded portions l2 pass through holes 12 in a disk 13 of metal. This disk is entirely separate from the disk 4 and has a somewhat different shape. A washer 14 is provided with holes 1 1 The washer 14 is made of insulating material having considerable mechanical strength. For this purpose hard rubber, hard fiber or the substance known in the elcctrose ploycd. Nuts 14 threaded internally, are screwed upon the threaded cylindrical portions of stems 12. The disk 13 is provided with a neck 15 which terminates in a socket 16, the latter'being provided internally with a thread 17 into which its an eye-bolt 1S threaded extcrn ally for the purpose.

material.

that the screw threaded stem-8 extends upwardly. Thesleeves 10 are now placed in the holes 5, and the'bolts 11 are next'dropped into those sleeves, the threaded portions 12 of these bolts thusprojecting considerably from the smaller ends of the sleeve. The washer 14 is now slipped over the stems 12 and lodged against the disk 4. The disk 13 is now slipped over the stems 11. The nuts 14 are now, screwed into position so as'to lock the disk 13, washer 14 'and disk 4 firmly together. The entire mechanism is placed in a mold and a quantity of insulating material molded and pressed around and between the parts. described so as to'form a spheroidal member 19, practicall enveloping the several metallic parts. T16 insulating material 19 is so shaped as to produce disks 20, each preferably of circular form and tapering in thickness toward its outer edge.

The member 19 of insulating material is further provided with annular beads 21 separated so as to form a groove 22 for girdling the center of the insulatingstrain. The structure is now mounted in position, the mechanical stress being upon the eye-bolts 9? and 18. A conductor 23, such as wire or cable, may now be rested within the grooves 22 intermediate of the annular beads 21. A tic wire 24 is next placed in position so as to secure the conductor 24 in fixed position. The ends 25 of this tie wire are now twisted so as to bend the conductor 24 firmly against the top of the strain insulator.

The closed metallic member made by the bridge 7, the stems6 and the disk 4 is so; disposed within the mass of insulating material 19 as to be completely embedded. In other words, this part of the construction virtually amounts to a strain member having a closed link completely embedded within insulating The eye-bolts 9, 18 and their connections together perform the ollice of a turnbuckle. In order that the operation of the turnbuckle may not place the strain member, or any part thcreof,'in a disadvan-- ta eous position, the disks 20 are made circula so that no matter what part of the disk may be upward or downward, the symmetry of the general structure is not disturbed, and its insulating qualities are not affected.

.It will be noted that in carrying out the objects above discussed :ny improved device servestho purpose of an ordinary strain insulator and a turnbuckle, and further performs the ollicc of an insulator for a conductor running in a difi'erent direction than the general direction of mechanical strain.

The sleeves 10 because of their peculiar conformity are ofgreat strength, and being frusto-conical in iform, they enable the mechanical stress of the bolt 11 to be distributed through the entire thickness of the disk 4, that is to say, a nuwhaniral stress tending to pull the bolts 11 from their l'astcnings must cause these bolts to we dge laterally against the sleeves 10 of insulating material; and

these sleeves are unable to yield-in a lateral direction because of the reinforcin action of the disk 14 encircling them. The great dength of the sleeves-10, due to distribution of mechanical strains over comparatively large areas, throws upon the disk 4 a mechanical stress extending ractically throughout the entire thickness oi the same, and thus tends to prevent the breaking of the bolts 11, and at the same time prevents destruction of the insulating sleeves 10.

It will be understood that, generally speaking, in insulating strains em )loying belts or their equivalents, there is ordinarily a great tendency for the bolts to pull in two, especially at points comparativel near their heads. This trouble is avoided y my construction. l

While the sleeves may be made of comparatively tough insulating material, such as ard rubber, or fiber, and the body portion 19 may be of less mechanical strength than the sleeves, I do not limit myself to any particular material for insulating urposes. Generally speaking, however, I pre or to employ a high quality of non-conducting material for the sleeves 10, and a chea or grade of the same for the member 19. either do I limit myself to the particular shape or conformity of any of the parts shown, nor to the exact mechanism disclosed.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent; l A strain insulator, comprisin a disk provided with holes of tapering (iameter, sleeves of insulating material fitted into said holes, bolts of taperin diameter fitted into said sleeves and exten ing through said disk, said bolts being separate from each other, mechanism connected with said bolts for ex erting thereupon a mechanical strain, and means for connecting said disk to a tension member.

2.) A strain insulator, comprising a disk provided with holes of frusto-conical form, sleeves of insulating material mounted within said holes and also of frusto-conic al form,- bolts provided with portions of frusto-conical form fitted into said sleeves, said bolts being separate from each other, a disk provided with apertures for receiving said bolts, and means for preventing the removal of said bolts from said second-mentioned disk.

3. A strain insulator, comprising a plurality of metallic tension members, separate from each other and disposed side by'side, means for insulating saidmcmbers from each other, and a member of insulating material enveloping said metallic tension members and provided with annular bends, said annulah beads extending entirely around said member of insulnl ing material and being separated so as to form therebetween a groove for holding a conductor, and disks of insulatin%n 1aterialin te ml with said member of insu atlng matena ter than said beads, sons to give tossaid member of insulating material substantially 1n material envelo ing the form of a spool.

4. The combination of a pair of metallic disks, a member of insulating matenal separating said disks and insulating the same from each other, each of said metallic disks being provided with holes and further provided with bolts, the bolts of one metallic disk extending into the holes of the other me tallic disk and being completely encircled by the same, and a body of insulating material and of much greaterdiame-f formed upon the outside of said metallic disks and fashioned at its ends into disks of comparatively large size.

5'. The combination of a plurality of metellic members, means for insulating the same from each other, and a body of insulatortions of said meta c members, sai bo y of insulating material being provided centrally with a groove.

In testimony'whereofl have signed my name to this specification in the presence of two subscribing witnesses.

' LOUIS STEINBERGER. Witnesses: I

WALTON HARRISON, JNo. M. RiTTER. 

